Designing for Degrowth: Energy Policy and the Architecture of Enough

The problem is not only how we build; it is that we keep building.

Much of the climate impact of the built environment is locked in long before occupancy.

The buildings and construction sector accounts for roughly 37 percent of global greenhouse gas emissions, as the world continues to add floor area at a pace equivalent to Paris every five days.

In response to this pressure, “green” projects are rising faster than ever, with over 29 billion square feet of LEED-certified space worldwide. Yet even these buildings begin with a substantial material carbon cost.

As electrical grids decarbonize, operational emissions from systems such as internal climate control and lighting are declining. What remains stubbornly high is embodied carbon, or the energy locked into the manufacturing and assembly of materials such as cement, steel, and aluminum. Even the most efficient new buildings can take 10 to 80 years to offset the emissions released during construction. That delay undermines near-term climate goals.

Building Less, Not Just Better

The path to a low-carbon built environment may depend not on new construction, but on reimagining what already exists. Adaptive reuse means transforming old buildings rather than demolishing them, thereby extending the life of what has already been paid for in emissions. Across multiple studies, reuse avoids 50 to 75 percent of embodied emissions compared to new construction, largely by preserving the most energy-intensive elements: the structural frame and envelope.

Still, demolition remains the norm. In the United States, an estimated 200,000 to 300,000 buildings are torn down each year, sending over 500 million tons of material and the associated embodied energy to landfills. Each demolition represents previously invested, and now wasted, climate capital.

The Policy Gap

Most architectural energy policies target operational efficiency, in the form of renewables and high-performance systems, while overlooking the carbon already embedded in materials. To meet national and city-level climate targets, policy must now begin accounting for embodied carbon.

Outdated regulations make that difficult. Most U.S. building codes were written for current construction standards, forcing reuse projects to meet requirements that older structures can rarely satisfy. Zoning laws and parking minimums are further disincentives, trapping buildings in regulatory barriers.

New York City’s adaptive-reuse framework demonstrates how zoning reform can shift the default toward reuse without outright mandates. Article I, Chapter 5 of the city’s Zoning Resolution allows owners of commercial or industrial buildings constructed before 1991 to convert them into housing or community spaces without having to meet full new-construction requirements.

While it does not prevent demolition, the policy removes major impediments that often make reuse impractical. Combined with New York City’s 2024 “City of Yes for Housing Opportunity” amendment, which further extends conversion eligibility to most non-residential buildings constructed prior to 1991 and eliminates parking minimums in transit-rich areas, New York City now offers a clear pathway for conversion. Together, these reforms make it far easier to transform aging buildings into housing.

At the federal level, incentives exist but fall short of maximizing the potential of reuse. The Historic Tax Credit offers a 20 percent credit for qualified expenses related to rehabilitation, and the Low-Income Housing Tax Credit supports affordable-housing rehabilitations; however, neither explicitly rewards the embodied-carbon savings of retaining existing structures. Similarly, the Inflation Reduction Act’s “Buy Clean” provision directed billions of dollars toward low-carbon materials for federal projects, though its funding has since been paused under the Trump administration.

In March 2025, U.S. Reps. Jimmy Gomez (CA-34), Mike Carey (OH-15), and John Larson (CT-01) introduced the Revitalizing Downtowns and Main Streets Act. Modeled after the Historic Tax Credit, the bill proposes a 20 percent tax credit for commercial-to-residential conversions, making it a promising initiative.

Expanding these incentives would signal a shift away from rewarding efficiency alone and toward prioritizing emissions avoidance.

Policies of Enough

Degrowth in the built environment does not mean limiting progress; it means redefining it. The architecture of enough challenges the assumption that progress depends on continual expansion. It positions design as a way to meet our needs within ecological limits, drawing value from what already exists.

To make adaptive reuse the rule rather than the exception, policymakers can start by adopting reuse-oriented code pathways, expanding reuse financing, and rewarding renovation over replacement in public procurement.

We cannot build our way out of the climate crisis. In the words of the former president of the American Institute of Architects, Carl Elefante, “the greenest building is the one that is already built.”

Phoebe Anagnos

Undergraduate Seminar Fellow

Phoebe Anagnos is a second-year student in the College of Arts and Sciences, majoring in both architecture and earth and environmental science.  Anagnos is also a 2025 Undergraduate Student Fellow.